Radiotuner



Feb. 26, 31935.l E. A. zDlG 1 1,992,407

BADIOTUNER iFiled mig. s, 195o sheets-sheet 1 ATTORNEYS Patented Feb. ze, 1935 i UNITED STATES PATENT. oi-Fries 1,992,407 RADIOTUNER "Ernest A. Zadig, 'New York, N. Y., assigner to 'Radio "Corporation of America, N. Y., aco'rporation of LDelaware Application August 6, 1930, Serial No. 473,482

16 Claims.

This invention relates to a method of `and means for-adjusting the tuning of apparatus for the reception of radiant energy `at diierent frequencies, and more particularly to a method `of and means for automatically tuning a radio receiver for the reception of currents transmitted at a selected frequency or from a selected stathe purpose of such description reference should be hadto the accompanying drawings forming a part hereof, and in which:

Fig. l is a front View of a radio receiver 4equipped withtuning means illustrating the vinvention;

2 lis aview to enlarged scale ofthe tuning 'mechanism substantially as it would appear 4if the front panel were removed from the receiver shown in Fig. l, the electrical control circuit being shown diagrammatically j Fig. 3 is a sectional view taken substantially on the line 3 3 of Fig. l, and to the same scale Fig. 4 is a fragmentary rear View of the lfront panel taken substantially on the line 4 4 of Fig. 3; Y l i Fig. 5 is a sectional view taken substantially on Ithelline 5 5 of Fig. 4; and

Fig. 6 is a sectional View to enlarged scale taken through one of the contact members substantially on the line 6 6 of Fig. 3.

Radio receivers used for the reception of broad# fcast programs having tuning mechanism which Vmore of the receiver has been shown than is Anecessary for a clear understanding of the illustrative embodiment of the invention.

Customarily the tuning control shaft of 'a radio Lreceiver has rigidly secured thereon an indicating disk or drum which is graduated, and Whichkis 'markedfusually with a series of numbers, -to provide areference scale. The receiver may be `tuned for Athe reception of currents from a selected sta- "tion by adjusting the tuning control until the Aand the tuning apparatus.

(Cl. Z50-40) predetermined point `on the scale corresponding- 4to the adjustment of the tuning mechanism Afor `the reception of the desired Acurrents registers witha reference zmark. Successful operation of such'a .receiver presupposes on the` partof the operator a knowledge of the scale reading `for tuning in any desired station, as well `as acertain amount of skill :in accurately "adjusting the tuning control. Y

In `most instances a radio receiver which is used for broadcast reception probably is not tuned in regularly on more than eight or ten diner-ent stations, and in .all .probability .the receiver will be used almost exclusivelyrfor the reception of currents from four or live of those'stations It is `customary to designate Aradio transmitting stations by-arbitrary arrangements of :symbols, usually letters, which arrangements, whether of letters or otherA symbols, commonlyare re-V `ferred to as the call letters of the stations. For a.

stations regularly transmitting 'broadcast programs the call letters usually are three or vfour in number, and at the present time in fthe United States the iirst letter is either K or W.

This `invention contemplates among other things the provisionof means for tuning a radio receiver, such means including va 4pre-selector device, whereby any one of the stations whose :programs are regularly received may be tuned Yin automatically merely by adjusting a pluralitylof pre-selector elements to display an arrangement of symbols Vrepresenting the station. ASuch. 'adjustment of the pre-selector elements may be accomplished in any suitable manner, vdependent upon theform which'the pre-selector elements take. In the illustrative embodiment the Spreselector elements are movable Arelative to aviixed reference mark. Conveniently the symbols are letters, and the receiver may be 'tuned yautomatically for the reception of currents from any Vselected station vlay-adjusting the'pre-selector elements to set up the call letters of the station.

Referring to 'the drawings for va .further .description ofthe illustrative embodiment,'and'r`st to Fig. l, a cabinet 11 houses the radio receiver Thecabinet lhas a front panel v12, and projecting .forwardly through a series of parallel elongate openings :13 in the panel are the levers -14 Which,.as will appear hereinafter, arey individually movable 4in ia vertical direction to control the adjustment of the pre-selector elements. Above the`slots `13 isaniopening r15 through 'the panel 1-2, which opening frames a series of symbols, conveniently letters,

vwhich are borne by the pre-selector elements,'and

secured to the bottom of an elongate frame-like member 2), which members will be referred to herein as the pre-selector elements, These preselector elements may be made of any suitable material, for example, brass, and desirably the openings in the elements are filled with sheets of translucent material, each bearing a series of symbols, for example letters. By adjusting the pre-selector elements vertically, the letters which are visible through the opening l5 in the front panel may be arranged in order as the call letters of V,a station whose currents are to be received. The left hand pre-selector element in the illustrative embodiment bears only the letters K and WW and a blanlr space, which for the reasons vpreviously set forth is adequate for present usage in l the- United States.

Referring to Figs. 3, 4 and 5, it will be seen that the. pre-selector elements conveniently are secured againstthe rear of the panel l2 by means of a series of parallel T and l.shaped strips 21 secured to the panel in a suitable manner to provide channels in which the elements are free to slide. Desirably, stop means are provided to inn sure accurate framing of any letter on a pre-selector element in the opening l5 in the panel. '.Converiently, such stop means comprise spring members 22, (Fig. 4) in the sides of channels for engaging notches 23, (Fig. 2)*on the sides of the pre-selector elements 20.

In the illustrative embodiment, each pre-selector element 20 is provided atits upper end with ran electrical contactmember which is mounted soz as to be insulated electrically from the ele- I ment. These contact members are designated on the ldrawings as 24, 25, 26 and 27, and an enlarged sectional view through one of the contact members is shown in Fig. Y6. Conveniently each contact member comprises a barrel 28 se- Y cured, as by means of a screw-threaded connection, on an insulating stud 32 passing through the upper end of the pre-selector element 25.

The forward end of the barrel 28 has a sharp cutting edge29, andinwardly of the outing edge a restricted opening. A plunger Contact 3i) is urged resiliently outwardly through the open end of the barrel 28, as by means ofa spiral coinpression spring 31 within the barrel. By reference to Figs. 2 and`4, it will be seen that the contact members 25 and 26 are offset laterally from the pre-selector elements in opposite directions, the reasonsvfor which will appear hereinafter. It will be noted that the stud 32 on which each of the contact members 24, 25, 26 and 27 is secured, slidably engages at its rear end either the panel 12 or one of the strips 21, thereby providing a rigid backing for the contact members.

As may best be rseen in Figs. 2 and 3, in the illustrative embodimentl the plunger contacts 30 of the several members 24, 25, 26 and 27 are urged bythe springs 31 against the face of a disk 4() which is mounted'on the main tuning control shaft 41 of the radio. receiver. The disk 40v is keyed to the shaft 41V so as to turn therewith, but is mounted for sliding movement along the shaft. The disk may be made `of any suitable Y material, but in the illustrative embodiment is made of an insulating material such as liber. On the face of the disk engaged by the plunger contacts 3u are two washer-like rings 42 and 43 of conducting material separated by a narrow ring 44 of insulation. The dimensions of the rings 42 and 43 and the mounting of the contact members 24, 25, 26 and 27 on the pre-selector elements 2D, are such that the plunger contacts 30 of the contact members 24 and 25 are pressed against the ring 42, and the plunger contacts 30 of the contact members 26 and 27 are, pressed against the ring 43. l

Removably secured on the face of the disk 40 so as to turn therewith, and between the plunger contacts 30 and the conducting rings 42 and 43, is a sheet' of insulating material 45, for example, paper. As will be seen in Fig. 2, the sheet 45 has a number of small perforations 46 overlying each of the conducting rings 42 and 43. These perforations are arranged in predetermined combinations to permit all of the contact plunger-s 3,0 to project through the insulating sheet 45 and complete electrical contacts with the rings 42 and 43 for certain predetermined adjustments of the pre-selector elements 2O and corresponding adjustments of the tuning control shaft 4l. The manner in which these perforations may be located and made will be described hereinafter.

Referring to Fig. 2, the contact members 25 and 26 are connected electrically by means of a flexible jumper 50 which permits free adjustment of each of the respectiveV pre-selector elements 20. The contact member 24 is connected as by means of a flexible lead 5l to one terminal of a source of electric power. The contact member 27 is connected through the flexible leads 52, a lamp 53, the lead 54, an electromagnet and a lead 56 to the other terminal of the source of electric power. Energization of the electromagnet 55 attracts the armature 6l thereby opening an electric circuit comprising a motor, (not shown) for adjusting the tuning control shaft 41, a suitable source of electric power, a lead 57, armature 61, lead 58, lamp 59 and lead 6G to the other side of the motor.

When the pre-selector elements 20 are arranged in such a manner that the contact members 24, 25, 26 and 27, register With perforations in the insulating sheet 45, an electrical circuit is completed from the source of power through the lead 51, contact member 24, ring 42, contact.

member 25, jumper 50, contact member'26, ring 43, contact member 27, lead 52, lamp 5S,V lead 54,

electromagnet 55 and lead 56 to the source of power. The lamp 53, which preferably is mounted in rear of the translucent sheets carried by the pre-selector members 20 will be lighted, and the electromagnet 55 will be energized to open the circuit of the tuning control motor. -The lamp 59 will be dark, and theadjustment of the tuning mechanism will not be changed until either the shaft 4l or one or more of the pre-selector elements 20 are adjusted toV disturb the electrical circuit for the electromagnet 55.

If it is desired to change the tuning of the receiver, the pre-selector elements 20 will be adljusted by moving the levers 14 until the letters visible through the opening 15 in theifront panel are the call lettersof the station whose program is to be received. It will be apparent that adjustmcnt of the pre-selector elements opensthe 'visible through the opening 15 in the panel, will indicate the condition of the apparatus. For example, the lamp 53 may give a White light and the lamp 59 a red-light.

If desired, means may be provided for preventing sounds issuing from the reproducer during the tuning operation. By way of example, the loud speaker `may be V.short circuited, as by means of a contact member 62 carried by the armature 61, and engaging, when the electromagnet 55 is deenergized torelea's'e the armature, leads'63 connected to the terminals of the loud speaker, (not shown). o

The tuning motor, (not shown) may be connected' in any suitable manner tothe control shaft 41, as by means of a frictional clutch arrangement, and when energized causes the shaft 41 to turn until a combination of perforations in the insulatingsheet 45 register with the contact members 24, 25, 26 and 27 of the pre-selector elements.` When such registration is secured, the electrical circuit for the lamp 53 and the electromagnet 55 is again completed, and the armature 61 is attracted to open the motor circuit and interrupt further adjustment of the tuning mechanism.

In many radio receivers in use at the present time, the tuning control shaft 'may be adjusted Desirably ment of the tuning mechanism is reached before obtaining registration of a combination ofV perfo- Vrations in the insulating sheet 45 with the contact members 24, 25, 26 and 27, the tuning motor will be automatically reversed in order to secure further adjustment of the tuning mechanism in the reverse direction until the aforesaid registration between the perforations and contact members is obtained.

For example, as shown in Fig. 2, the disk 45 may be provided adjacent its edge with two rearwardly projecting pins 47 and 48 arranged at diametrically opposite points. `As the shaft 41 approaches one limit of its turningv movement the pin 47 engages one end of a lever 80 which is pivotally mounted intermediate its ends at a. Also pivotally mounted at 80a. is a switch arm 82. Means such as a compression spring `83 connecting the lever 80 and the switch arm 82 completes a toggle mechanism for turning the switch arm 82. Further turning of the shaft 4l actuates the toggle to shiftthe contact 81V on the end of the switch arm 82 from engagement with a contact 85 into'engagement withaJ contact 84. The contacts 81, 84 and 85 are suitably connected by leads 86 to the tuning control motor so that actuation of the toggle switch reverses the motor. When the shaft 41 is turning in the opposite di- -rection and approaches-the limit of its turning movement, the pin 48 engages the lever 80 to actuate `the switch in a similar manner in the reverse direction to reversethe motor.

The insulating sheet 45 is secured on the face of the disk 40 so as to prevent relative turning movement, as by means of one or more screws 49, and the perfcrations 46 may be made in any convenient manner. In the embodimentof `the invention disclosed the perforations 46 in the sheet maybe located and made in the following manner. The `disk 40 is slidably mounted on the shaft 41, and normally is pressedr rearwardly face of the disk 45 and a screw 65 in the end of the shaft 41.' `The rear of the disk is provided with a hub 66` having an annular channel 67 which is engaged, as at diametrically opposite points, by a yoke member 68. vThe yoke member is pivoted at its lower end on a suitable support, conveniently a part of the frame supporting the rotatable shaft 41. Engaging the yoke 68 ntermediate its ends, is a link 69, conveniently extending rearwardly through the back of the receiver and having at its end a push button 70, whereby the link may be manually actuated to cause the yoke 68 to move the disk 40 forwardly against the pressure of the spring 64 to press the sheet 45 against the cutting edges 29 contact members 24, 25, 26 and 27. By exerting pressure on the button 70, perforations will be made in the sheet 45, or alternately the sheet will be marked by the cutting edges 29 so that it can be subsequently perforated in some other suitable manner. When the button 70 is released, the disk 40 is moved away from the contact members under the influence of the spring 64, and the punched-out portions of paper are pushed out of the ends of the contact members bythe plungers 30 under the influence of the springs 31.

It will be apparent that if, prior to actuating of the the perforating mechanism as `above described,

the pre-selector elements 20 have been adjusted to show the callv letters of a station whose Acurrents are to be received, and the receiver has been ofthe station. Obviously, by repeating this procedure for other transmitting stations, it will be possible to tune the receiver automatically forl any one of a limited numberl of stations Whose programs are regularly received.

Manual adjustment of the tuning mechanism for the reception of currents from stations other than those regularly received, may be made in the usual manner by means of any suitable mechanism, for example, by means of a disk `7,5 fric- `tionally engaging the edge of the disk 40, and sein the power circuit Ato theV motor.

' If the tuningV control shaft 41 may be turned `only through an arc of about 189, the perforations inthe sheet'45 will be arranged on substantially one-half ofthe sheet. the sheet 45 may beutilized, as shown in Fig. 2,

for a reference scale, a portion of which is visi- Vble through the opening 17 in the front panel to -indicate the tuning of the receiver.

In the operation of the illustrative embodiment, the receiver is tuned manually to receive currents from a station whose programs are to be received more or less regularly. The pre-selector elements 20 are adjusted to show the station call letters through the opening 15 in the front panel, and the button 70 is actuated to perforate the sheet 45.

This procedure is repeated to perforate the'sheet The other half of be tuned automatically for the reception of currents from any one of these stations by closing the energizing circuit for the tuning motor and adjusting the pre-selector elementsto display the call letters of the desired station.

' The description of the illustrative embodiment is not intended as defining the limits of the invention, and it will be understood ythe invention may be variously modied and embodied within the scope of the appended claims.

I claim:

1.1In apparatus for receiving radiant energy, the combination of tuning means, power means for Iadjusting the'tuning means for the reception of currents of different frequencies, pre-selector means comprising a plurality of individually adjustable elements each bearing a plurality of letters, means for adjusting said elements with reference to a xed mark to arrange in proper sequence the call letters of a selected transmitting station whose currents are to be received, and means operating automatically in response `to such adjustment to cause said power means to Vadjust said tuning means for the reception of bols representing atransmitting station whose currents are to be received, and means operative automatically in response to the adjustment of said elements to cause said power means to adjust said tuning means for reception of the desired currents. Y

3. In apparatus for receiving radiant energy, the combination of tuning means, a motor for adjusting said-tuning means, a plurality of pre-selector elements each bearing a plurality of symbols, means whereby said pre-selector elements may be successively arranged in a plurality of different predetermined combinations of said symbols representing different transmitting stations, means including a relatively mobile perforated element, controlled by said pre-selector elements and controlling said motor for automatically adjusting said tuning means to the predetermined position corresponding to any one of said several predetermined combinations of saidpre-selector l elements which may be arranged.

Vmeans for causing said motor to adjust said tuning means to a predetermined position for the reception of the desired signals, and for automatically interrupting further adjustment of said tuning means when said predetermined position is reached.

5. In apparatus for receiving radiant energy, the combination of tuning means, a motorrior adjustingl said tuning means, a plurality of pre-selector elements, means whereby said pre-selector elements may be successively adjusted to a plurality of different predetermined combinations representing different transmitting stations, means controlled by said pre-selector elements and controlling said motor for automatically adjusting said tuning means to the predetermined position corresponding to any one of said several predetermined combinations of saidpre-selector `elements which may be arranged, said last mentioned means comprising a'plurality of electrical contacts and a relatively movable perforated sheet controlling the completion of an electrical circuit through said contacts.

6. In apparatus for receiving radiant energy, the combination of tuning means, station pre-selector means, means for' adjusting said pre-selector means to establish an arrangement representing the call letters of a transmitting station whose signals are to be received, and motor circuitmeans including a disc perforatedginV a predetermined manner, controlled by said pre-selector means, said pre-selector means including :at least one `contacter adapted to cooperate with at least one disc perforation to close said circuit ior automatically adjusting said tuning means to the corre-H sponding predetermined position for the reception ofwsignals from'tl'ie desired transmitting station.

'7. In apparatus for receiving radiant energy, the combination'of tuning means,l means for adjusting said tuning means for the reception ofcurrents of different frequencies, a plurality of. pre-selector elements bearing symbols and individually adjustable to bringthe symbols into combinations representing different transmitting waves, means operativev automatically when said pre-selector elements are arranged in a combination other than that corresponding to the adjustment of the tuning means to cause' said second mentioned means to adjust said tuning means to a predetermined position for the reception of the transmitting wave vcorresponding to said larrangement of the pre-selector elements, and

means operative when said tuning adjustment'is completed to discontinuefurther adjustment of Said tuning means.

8. In apparatus for receiving radiant energy, the combination of tuning means, means for adjusting said tuning means for the reception of currents of different'frequencies, a plurality of pre-selector elements bearing symbols and individually adjustable to a plurality of diiferent predetermined symbol combinations representing diierent transmitting stations, an electrical circuit, means for changing automatically `the char- Y acteristics of said electrical circuit when said preselector elementsare arranged in a combination other than that corresponding to the adjustment 0f the tuning means, means operative upon such change in the characteristics `of said electrical circuit to cause said second mentioned means to adjust said tuning means to a predetermined position corresponding to saidnew arrangement of ries of electrical contact members, a sheet of insulating material having a plurality of perforations interposed between said two series of contact members, means for individually adjusting the contact members of one series relative to each other, and means operative automatically upon such adjustment of the contact members to adjust said tuning means and simultaneously move said perforated sheet to bring perforations in the latter into register with the adjusted contact members and complete `an electrical circuit through said two series of contact members, and means operative thereupon to discontinue further adjustment of said tuning means and further movement of said sheet.

l0. In apparatus for receiving radiant energy, the combination of tuning means, means for adjusting said tunng'means for the reception of currents of different frequencies, means for controlling said adjusting means comprising a plurality of electrical contact members, a perforated Sheet controlling the completion of an electrical circuit through said contact members, means for individually adjusting the contact members relative to each other, and means operative automatically upon such adjustment of the contact members to adjust said tuning means and simultaneously move said perforated sheet to bring perforations in the latter into registerwith the adjusted Contact members, andrmeans operative thereupon to discontinue further adjustment of said tuning means and further movement of said sheet,

11. In apparatus for receiving radiant energy, comprising station pre-selector means, tuning mechanism, an electrical control circuit for said tuning mechanism including a plurality of contacts in said pre-selector means, and a circuit determining sheet associated with said tuning mechanism, means for adjusting the tuning mechanism to receive' desired currents, means for adjusting the pre-selector means to display a series of symbols representing the station transmitting the desired currents, and means for perforating the circuit determining sheet when said adjustments have been made.

12. In apparatus for receiving radiant energy, the combination of tuning means, means for adjusting said tuning means, a plurality of elements each bearing a plurality of symbols, means for adjusting said plurality of elements individually to arrange a sequence of symbols representing a transmitting station Whose currents are to be received, and means including a mobile perforated card for rendering said tuning adjusting means operative when said elements have been adjusted.

13. In apparatus for receiving radiant energy, the combination of tuning means, current consuming means for adjusting said tuning means for the reception of currents of different frequencies, station pre-selector means, a perforated disc for controlling said tuning adjusting means, means giving a signal during adjustment of the tuning means, means giving a different signal when the tuning means` has been adjusted to a pre-selected position, said disc comprising a card provided with va plurality of apertures corresponding to different stations and contacts carried by said pre-selector means cooperating with the apertures insaid card to control the current through said current consuming means.

14. The combination set forth in the preceding claim, in which the several means for giving different signals comprise differently colored lights.

15. In combination, in a radio receiver, a. tuningmeans, power means for adjusting said tuning means, an electrical circuit including said power means, a plurality of independently vertically adjustable station pre-selector means arranged to render said electrical circuit operative at predetermined positions of said selector means, and a mobile card disposed in operative relation with said electrical circuit and said pre-selector means and including perforations arranged for controlling the operation of said power means.

16. In apparatus for receiving radiant energy, the combination of a tuning member, a plurality of independently adjustable station pre-selector means, means permitting the adjustment of said preselector means, means for automatically adjusting said tuning member in accordance with the adjustment of said pre-selector means comprising an electrical circuit and a circuit control discadjustable with said tuning member, means for indicating continuously the adjustment of Said tuning member, and means including` an index carried by eachof said pre-selector means for indicating the adjustment thereof.

ERNEST A. ZADIG. 

